PHYSICO-CHEMICAL STUDIES ON SOME HYDROXYAZO COMPOUNDS DERIVED FROM 2,6-DIAMINOPYRIDINE AND THEIR METAL COMPLEXES

Abstract

In this thesis, a series ofx-phenylazo derivatives of 2,6-diaminopyridine was studied physico-chemically . The azo compounds and some of their Cu(II) , Co(II) , Zn(II) and Ni(II) complexes have been prepared and characterized on the basis elemental and thermal analysis, electronic and IR spectra data . The effect of both pH and pure organic solvents on the electronic absorption spectra of the compounds was studied . The studies are aimed to assign the different spectral bands , determination of the equilibrium and the ionization constants of the compounds and stability constants of the metal-ligand complexes .

Moreover, the chelating tendencies towards the studied metal ions of the subject compounds have been also studied using pH­ metric technique . The data indicate clearly that , The free compounds and their metal chelates have the azohydrazone nature . The complexation equililiba for these reagents with copper(II) were studied spectrophotometrically at different pH values to investigate the different species of the complexes in solutions and calculation of the molar absorptivity , eqiulibrium constants and stability constants . The ability of these reagents for determining copper(II) was tested .